Ethernet Modbus..

Report
Industrial Communication
Ethernet Modbus TCP/IP
1
Ethernet Is a Network
● History
● Developed by Xerox Palo Alto Research Centre (PARC) (1973 - 1975)
● First standard to be published in 1980 (IEEE 802.3)
● Network
● System resources shared
across the entire platform.
AL GORE
● Sharing Information
● Monitor
● Control
● Reporting
2
Ethernet Everywhere
• From enterprise & IT level,
through control level, to end
devices…
• Ethernet is our “DNA”…
Ethernet drives
3
Ethernet: The backbone of PlantStruxure
Enterprise
Ethernet
Plant
Standard
Open
Process
Flexible
Efficient
PAC
Field
PAC
Transparent
Sustainable
Robust
Reliable
4
The TCP/IP Suite
What is it?
OSI Model
7
Application
6
Presentation
5
Session
4
Application
4
Transport
3
Transport
3
Network
2
Network
2
Data Link
1
Data Link / Physical
1
Physical
TCP/IP Model
9
The TCP/IP Suite
What is it?
Application
BOOTP
Modbus
Transport
Network
HTTP
OPC
SNMP
DHCP
UDP
TCP
OSPF
IGRP
CIP
ICMP
IGMP
IP
Data Link
Physical
QoS
IEEE 802.3 Ethernet
RSTP
10
Modbus TCP/IP
Defined in terms of OSI model?
Application
BOOTP
Modbus
HTTP
Transport
Network
OPC
DHCP
UDP
TCP
OSPF
IGRP
SNMP
CIP
ICMP
IGMP
IP
Data Link
Physical
QoS
IEEE 802.3 Ethernet
RSTP
11
Ethernet Modbus TCP/IP
● OSI Reference Model - Modbus frames embedded within Ethernet.
13
Servers and Clients
Server - computer that is able to share a resource.
Client - computer requests information from a Server.
Examples of Client/Server models:
• Email Server / Email Program
• Web Server / Browser
• FTP Server / FTP Client
• Modbus Slave / Modbus Master
14
Networking in Windows
Four elements must be configured in order to allow
devices to talk to each other.
● Adaptor
● Protocol
● Client
● Service
15
Adaptors
Windows operating systems have inbuilt functionality
Note: Screen capture from Window XP OS
16
Protocol
● Think of Protocol like a language..
● Set of rules or standards vendors follow to allow
computers of different types to talk to each other.
17
TCP (Transport Control Protocol)
● Port and socket concept
● PORT - Modbus port 502, HTTP Web port 80, SNMP port 161, BootP etc…
●Server devices may be running multiple services
●These services listen on different TCP ports for a specific request
● SOCKET - Client device sends an IP message which includes the source
port number and destination port number to establish a connection between
two devices.
Ports
Client
Source Port number x
80
Server
Destination Port 502
161
Destination Port 80
Source Port number y
502
172.16.4.2
172.16.4.1
HTTP
SNMP
Ports number
23 Telnet
50 SMTP
67 DHCP
80 HTTP
161 SNMP
502 Modbus
referred to as a Socket connection
Modbus TCP
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TCP (Cont.)
● Socket management can involve multiple connections
● A Client can have multiple connections to the same Server service
● A Server can have multiple Clients connected to the same service
Client x
Client has a 2
connections to
the same server.
Socket
1
2
Source port
3000
3001
Dest port
502
80
Socket
1
Source port
3003
Dest port
502
Server
Server has 2 clients
connected to the
same service (502).
172.16.4.1
Client y
172.16.4.3
172.16.4.2
19
TCP Connections
● Point to point messaging protocol
● Uses a handshake process to establish a connection
● Accounts for each byte of sent and received to guarantee delivery
● Connection is managed by setting bits in the TCP message to request
(SYN), acknowledge (ACK), terminate or abort the connection (FIN)
Client
O
P
E
N
Server
C
L
O
S
E
20
IP (Internet Protocol)
● IP: Messaging Protocol Operating at OSI Layer 3 (Network layer)
● IP is responsible for:
● Transmitting the message to the destination IP address to either the local
network or to a remote network.
● Fragmenting a packet that is larger than the maximum transmission size
unit (MTU) to send as multiple packets and de-fragment the packet at the
destination level.
Makes no guarantee that the message will reach its destination!
Remember…….The reliability is done by the Transport layer
21
What is an IP address?
●IP Address is made up of Four sets of eight bits separated
by a decimal place holder
.
.
.
11000000 10101000 00000000 11010100
When binary bits are translated into decimal they
become the numbers from 0 to 255
192.168. 0.212
Four sets of three decimal
numbers (or octets)
22
IP Address
Each devices on the network can have a unique address
regardless of vendor or OS.
23
IP Address
IP Address identifies two things:
● The Identity of the Network
● The Identity of the Host
− Computer
− Printer
− PLCs, HMI, I/O Device etc…
24
IP Address Assignment
● Default IP Address
● Derived from the factory and unique MAC address
Quantum/Momentum/Advantys/M340
MAC @
IP @
00 - 00 - 54 - 12 - 0C - AF
= 84 . 18 . 12 . 175
- Hex to Decimal conversion of last 4 bytes
● Unique IP Addresses for Each Device
The default IP address format is 84.x.x.x:
84: a fixed value
x: The last three fields in the default IP address are composed of the decimal
equivalents of the last three hexadecimal bytes in the MAC address.
25
IP Address Assignment
For example: Device MAC address 0000531201C4
You are concerned only with the last three bytes 12-01-C4
●Convert these bytes from hexadecimal to decimal.
Hexadecimal
Decimal
12
18
01
01
c4
196
●The hexadecimal values 12, 01, and C4 correspond to
decimal values of 18, 1, and 196, respectively.
●These values are combined with the default IP address
format (84.x.x.x) to yield a default IP address of 84.18.1.196
26
IP Assignment
● IP Assignment - By default a device IP address uses the MAC
address assignment.
There are two ways to assign a unique IP address:
● Static: IP address is keyed directly into the device using software or
web interface. In a case of a computer, the IP address is set using the
operating system (Control Panel inside Windows for example)
● Dynamic: A server assigns automatically the IP address to the device.
27
Classful IP Address
● There are 4 main address classes
larger
● Class A - Used for
networks
●IP Address Range : 1.0.0.0 to 127.255.255.254
●Default subnet mask : 255.0.0.0 – 16,777,216 hosts number
● Class B - Used for Medium networks (ex. Schneider Electric)
●IP Address range : 128.0.0.0 to 191.255.255.254
●Default subnet mask : 255.255.0.0 – 65,534 hosts number
● Class C - Used for smaller network and individual users
●IP Address range : 192.0.0.0 to 223.255.255.254
●Default subnet mask : 255.255.255.0 - 254 hosts number
● Class D - Used for Multicast groups
●IP Address range : 224.0.0.0 to 239.255.255.255
●Devices cannot be assigned IP addresses in the multicast range
● The Class E is reserved for the future : 240.0.0.0 to 255.255.255.255
28
Special IP Addresses
● Loopback
● IP address = 127.0.0.1
● Reserved for loopback (host connecting to itself)
●Ex. A web browser connecting to a web server running on the same PC
● Broadcast
● IP address = 255.255.255.255
● Used by the network management or diagnostics is addressed to all devices
on the network.
29
Subnet Mask
● Used to determine if the remote device is on a local or remote network
● The mask separates the network portion of the IP address from the host
portion of the IP address
● The sending device uses its configured subnet mask to perform a Boolean
AND operation with both its local IP address and the IP address of the
remote device to connect to
Local device
Remote device
IP Address 172.16.5.20
Subnet Mask 255.255.255.0
Result
IP Address 172.16.4.20
Subnet Mask 255.255.255.0
Result
10101100.00010000.00000101.00010100
AND 11111111.11111111.11111111.00000000
10101100.00010000.00000101.00000000
10101100.00010000.00000100.00010100
AND 11111111.11111111.11111111.00000000
10101100.00010000.00000100.00000000
30
Troubleshoot TCP/IP
● In Windows Network > Properties
● Monitoring Free Tool: WireShark
http://www.wireshark.org/
Wireshark is a free and open-source packet analyzer. It is used
for network troubleshooting, analysis, software and communications protocol
development, and education.
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Troubleshoot TCP/IP
● Ping Command
● Used to check a connection
● Launched from the DOS CMD window (under XP)
32
Exercises
Lab 1 Set Laptop IP Address
– Find your IP address (record it for future use)
– Change the IP address into 192.168.1.1X (X=Group Number)
Troubleshoot TCP/IP
– Use PING command to ping first your own laptop then PING
other Laptops connected to the RSTP ring.
33
Dynamic Assignment
● IP Assignment Given By Servers
Switch
Request for IP @
Server
Switch
Your IP @
Client
34
BootP Server
● Server Has a Populated List of Devices
● Devices identified with their MAC address
Device #1
My MAC address is 00.80.F4.FF.00.D5,
Can I get an IP Address?
Sure! You are listed in my address table.
Take this address: 192.168.0.23
Device #2
Master (Server)
00.80.F4.FF.00.D5
192.168.0.23
00.80.F4.FF.44.21
192.168.0.81
00.80.F4.FF.F2.15
192.168.0.40
My MAC address is 45.80.F4.FF.33.12,
Can I get an IP Address?
Sorry, you are not listed into my address
table. Use your default IP address
35
BootP Server (Cont.)
● Example in Unity Pro
● Limitation: Device Cannot Be Changed without Reconfiguration
● As each device has a unique MAC address, replacing a failed device needs
a reconfiguration of the BootP Address Server table.
36
DHCP Server
● Same As BootP but Based on Role Name
● User configurable names used instead of MAC Addresses
Device #1
My name is STBNIP2212_023,
Can I get an IP Address?
Sure! You are listed in my address table.
Take this address: 192.168.0.23
Device #2
Master (Server)
STBNIP2212_023
192.168.0.23
TesysT_046
192.168.0.87
ATV71_555
192.168.0.21
My name is TesysT_072,
Can I get an IP Address?
Sorry, you are not listed into my address
table. Use your default IP address
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DHCP: How To Create Role Names
● Depends on The Device
● Using embedded HMI (ex: ATV71)
● Using web based applications (ex: Advantys STB)
● Using dedicated applications (ex: Unity Pro)
● Using hardware switches (ex: Tesys T, Advantys STB)
● Hardware Switches Example:
● Base name + Custom number derived from Switches
STBNIP2212_123
38
DHCP Server
● Example with Unity Pro
● Advantage: Easiness of Replacement
● Compared to the BootP method, replacing a failed device with DHCP
doesn’t need to reconfigure the PLC application.
39
FDR Server
● Additional Feature of Fast Device Recovery Server.
● Send the stored configuration inside a replaced device
Master (Server)
Device #1
My name is TesysT_072,
Save my settings now!
TesysT_072
192.168.0.87
Saved Config. of TesysT_072
Device #1
My name is TesysT_072,
Can I get an IP Address?
New Device
Sure! You are listed in my table.
Take this address: 192.168.0.87
Moreover, I found a configuration
corresponding to your role name.
Here is your new configuration.
Master (Server)
TesysT_072
192.168.0.87
Saved Config. of TesysT_072
40
ARP
● Address Resolution Protocol
● Request to obtain IP address
● Duplicate Address Check
●Device issues ARP for the IP address it intends to take
●If no response, the device assumes the IP address
●If there is a response, the device should not assume the IP (duplicate
address)
● Once the IP has been determined to be available
● Device issues a Gratuitous ARP (Includes Source IP and MAC address
information)
●Used to populate device list in the other devices and routers
● Advertises to others its availability on the network
●Allows devices to communicate with it now that it’s available
41
UDP (User Datagram Protocol)
● Transport protocol like TCP but without Acknowledgement
● Provides an unreliable mechanism to transport data
● Messages can be lost (not acknowledgment of the packet)
● Retries and data integrity can be provided by the application layer
● Requires less processing overhead that TCP
● Without ordering messages and managing connections. it is faster than TCP
● The network interface does not have as much work to do as with TCP
● Allows the Broadcast message, unlike TCP that requires a dedicated socket
between the end device. Applications example using UDP :
● Simple Network Management Protocol (SNMP)
● Network Time Protocol (NTP)
● BootP and DHCP
● Global Data (Real Time Publish Subscribe)
● Streaming video i.e. YouTube
42
Network Design: Media
● Media
● Copper media
● Twisted pairs wires
● Easy to install : low cost installation
● Fiber optic
● Adapt different types of media
● Using over long distances or harsh industrial environment
44
Network Design: Copper Media
● Rated by category
● Categories established by ANSI/EIA/TIA Committee
● Industrial applications recommend Shielded media for additional protection
from external sources of interference
● Uses Standard 8 pin RJ-45 Connector
● Cat 5 : Minimum required for 100Mbs Ethernet (unshielded cable)
● Cat 5e : Enhanced for 100Mbs Full Duplex operation (shielded cable)
● Cat 6 : New standard for 1 Gbs operation
The maximum length of one segment
is 100 meters at 10, 100, 1000 Mbit/s.
45
Network Design: Fiber Optic
● Glass or plastic fiber designed to guide light along its length by total internal
reflection.
● Permits digital data transmission over longer distances and at higher data
rates than other forms of wired and wireless communications (up to 20km)
ST connector
Bayonet style connector
SC connector
Keyed square connector
May be coupled together
LC connector
MTRJ connector
Newer keyed Fiber connector
Smaller form factor : higher density
Small form factor, keyed connector
46
Network Design: Components
● Hubs or switches
● Hubs are not recommended for industrial application
Connexium Switch
● Transceivers
● Adapt different types of media
Ex. 499NTR10100 : converter electrical signal to optic signal
499NTR10100
● Routers
● Used to route information between networks
● Firewalls
● Cybersecurity restricted access Security Appliance SA
TCSEFEA23F3F20
47
Network Design: Hubs
● Half Duplex (Collisions)
● Each and every ‘frame’ is repeated out all ports by hub
● All ‘nodes’ listen to see if they are the receiver of the frame
● As more nodes are added and collisions increase, performance decreases
● If two devices transmit simultaneously, a collision occurs
Hub
Collision
Transmitter 1
Receiver
Transmitter 2
48
Network Design: Switch
● Full Duplex (Collisions)
● Learns the IP addresses of the devices attached to each port
● Passes only messages to targeted devices that are currently active
● Full duplex ports can simultaneously transmit and receive a message
Switch
full
duplex
Transmitter 1
The Switches are strongly recommended
for the Industrial application.
Receiver
Transmitter 2
49
Network Design: Routers
● Routing data between different sub networks
● Act as a Gateway (IP address to be defined)
● A router has an interface for each different networks. A table of those
interfaces tells the router on which interface to send the packet
PLC
Router
172.16.4.254
172.16.5.254
172.16.5.1
172.16.4.1
Local Subnet
172.16.4.2
Each router interface is the default
gateway for that subnet
Remote Subnet
Nota : If there is not a router on the local network, the default gateway can be left blank or 0.0.0.0
50
Network Design: Firewalls
● Only authorized devices and message traffic can communicate through
the firewall to devices in a secure zone
● The user selects devices and message traffic that have access to
devices in the secure zone
Unprotected Zone
Secure Zone
Firewall
All Communication Traffic
Authorized
Switch
Traffic OK
Control Device
External Port
Host Device
Connection
Internal Port
Connection
Unauthorized
Traffic Rejected
51
Network Design: Topologies
Bus topology
Switches in series, end devices
connected to switches
Tree / Star topology
Switches in a star or tee-like
arrangement
Ring topology
Daisy Chain topology
Switches form a ring or circle
No switches needed
52
Network Design: Point to Point Cables
● Straight Cable
● Connect end devices to hubs or switches
Switch or Hub
End Device
● Crossed Cables
● Connect hubs or switches together
Switch or Hub
Switch or Hub
53
Ethernet Module Utilities
● IP Configuration
● Messaging
● Access rights from other devices.
● SNMP (Simple Network Management Protocol)
● Used by software monitor and manage devices on an IP network. (ConnexView)
● SMTP (Simple Mail Transfer Protocol)
● Parameters for sending and receiving e-mail.
● IO Scanning
● Global Data
● Address Server
● configures the DHCP and BOOTP services included in the module.
● NTP (network time protocol)
● Define the time synchronisation server
● Common Words (Premium Only)
● used to configure words shared on EthWay
● Bandwith
● estimation of the Bandwith taken by the different services.
57
BEFORE GOING TO LAB 2
LET’S FIRST LEARN MORE ABOUT
CONNEXIUM NETWORK MANAGER
AFTER A SHORT BREAK…
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